Managing Risk of Custom Manure Application and PEDV Spread

Biosecurity measures have been standard operating procedure for custom manure applicators for a long time, but the presence of porcine epidemic diarrhea virus (PEDV) has forced them to revisit or step up their practices.

“I don’t want to create paranoia, because I’m not aware of any cases of manure applicators spreading PEDV, but we still need to be vigilant,” says John Carney, executive director of the Manitoba Livestock Manure Management Initiative. “We can’t eliminate the risk, but we can manage it through communication and strong biosecurity.”

Carney says custom manure applicators have done a good job of managing the risk with procedures, training, equipment and supervision, “but all of these things cost money, so that’s where judgment comes in, so we need to act to ensure the right actions are followed every time.”

A lot has been learned since PEDV was first confirmed in the United States on May 17, 2013, but there is still a lot that is unknown.

Lisa Becton, a veterinarian and director of swine health information and research for the National Pork Board (NPB), says what we have learned is that large amounts of the virus are shed by pigs during the early infection, and it takes a small amount of the virus to cause infection in other pigs. “PEDV is spread through contact with contaminated manure,” Becton says, so anything that comes in contact with manure can be a potential source of infection.”

Researchers have found that the virus is not shed in the respiratory tract and is not aerosolized, but there is evidence that the virus can be moved in the wind on dust particles and even moisture, thus “it brings up a concern about the proximity of farms,” she says.

With that in mind, custom manure applicators need to maintain that vigilance to prevent the spread of PEDV and other diseases. Carney’s organization and Kevin Erb of the University of Wisconsin Extension collaborated to conduct a survey of custom manure applicators, the results of which were announced at the North American Manure Expo held in early July in Springfield, MO. With the basis of the NPB Manure Applicator Protocol for biosecurity in hand, the survey concentrated on what applicators are doing before pumping and after pumping manure for customers. “I’m a firm believer of ‘start right, end right’,” Carney says.

Communication and biosecurity are key for custom applicators and their clients, and as the survey showed, communication is the easy part. Applicators were asked to rate in terms of ease how it was to implement different PEDV strategies in the manure hauling process. “Over 90% shared that they contact the producer about their plan for application and how they plan to arrive to their farmsite,” Carney says. Where it got difficult was on clean execution: 23% of the custom applicators surveyed said it was difficult to plan an entrance and exit with minimal crossover with all other farm traffic, and it was even more difficult (32%) to identify “lines of separation” on the farm. The “line of separation” defines the area that is to be used by the manure haulers and the area to be used by all daily farm traffic and personnel.

Carney says determining such “lines of separation,” and maintaining them, is important. “It may be as simple as putting up pylons connected with yellow hazard tape during manure application to physically mark the line to indicate to the barn staff and daily farm traffic that we’re supposed to be over here, and the manure applicators are to be over there.”

Biosecurity on a hog farm is more in-depth than simply putting up pylons and hazard tape. Communication and clear expectations understood by all parties are necessary steps in the process. For more information on the NPB protocol, visit www.pork.org/filelibrary/PEDV Biosecure Manure Fact Sheet.pdf. Look for the September issue of National Hog Farmer for a more in-depth article on manure handling and PEDV biosecurity concerns.